Question: How many significant figures does $09.54135000$ have?
Answer: Identify the non-zero digits and any zeros between them. These are all significant. $0{9.54135}000$ Leading zeros are not significant. $\color{orange}{0}{9.54135}000$ Since there is a decimal, trailing zeros are significant. $\color{orange}{0}{9.54135000}$ Counting all the significant digits gives us 9.